Poly-cyclohexyl-naphthalenes



utnted Jan. 14, 1941 *N'ITED STATES PATEN FICE POLY- CYCLOHEXYL-NAPHTHALENES Frank B. Smith and Harold W. Moll, Midland,

Mich, minors to The Dow Chemical Company, Midland, Mich" a corporation of Mich This invention concerns certain new chemical compounds, namely cyclohexyl-naphthalenes containing at least three cyclohexyl groups per naphthalene nucleus. All such compounds are herein referred to as "poly-cyclohexyl-naphthalenes." The invention also concerns mixtures 01 such compounds.

The poly-cyclohexyl-naphthalenes and their mixtures vary in physical properties from very viscous, high-boiling liquids to glass-like resinous solids, depending upon the number of cyclohexyl groups which have been introduced into the naphthalene molecule. They are substantially insoluble in water. but are readily dissolved by a number of organic solvents, such as carbon tetrachloride, toluene, benzene, chlorbenzene, etc. They may be employed as plasticizing agents for cellulose ethers, e. g. ethyl cellulose, benzyl cellulose, etc., to prepare flexible films and foils having very high surface hardness. The lower cyclohexylated naphthalenes, i. e. monoand di cyclohexyl-naphthalenes, have little, it any, plasticizing action on cellulose ethers.

The new poly-cyclohexyl-naphthalenes are peratures may be employed. The reaction is usually complete in from 1 to 10 hours and, ii desired, the time may be shortened by carrying out the reaction under pressure in a closed vessel. When the reaction is complete, the catalyst is removed and the mixture is iractionally distilled under vacuum.

The fraction distilling at temperatures between about 220 C. and about 312. C. under 20 millimeters pressure is a viscous yellow liquid, consisting almost entirely of a mixture of monoand di-cyclohexyl-naphthalenes. Such liquid mixture constitutes a valuable by-product which may be iurther reacted with a cyclohexylating agent to prepare the more highly substituted compounds, or which may be employed as such as a dielectric fluid, etc. The poly-cyclohexyl-naphthalenes are obtained as a very viscous liquid mixture distilling at temperatures above about 312 C. at 20 millimeters pressure. I1 desired,- such mixed product may be employed directly as a plastlcizing agent or it may be further fractionaliy distilled to obtain fractions representing isomeric tri-cyelohexyl-naphthalenes, tetraprepared by reacting naphthalene with a cyclocyclohexyl-naphthalenes, etc. The fraction dishexylating agent, such as cyclohexene, cyclohexyl tilling at temperatures between about 312 C. bromide, cyclohexyl chloride, etc., in the presence under 20 millimeters pressure and about 305 C. of an alkylation catalyst, e. g. aluminum chloride, under 5 millimeters pressure consists essentially v iron chloride, boron trliiuoride, activated bleachof isomeric tri-cyclohexyl-naphthalenes and is ing earths such as Retrol and Tonsil, etc. In a particularly valuable as a plasticizing agent for preierred mode of operation, the new products ethyl cellulose compositions.

' We Prepared by reacting cyclohexene with naph- The following examples illustrate several ways thalene empmymg Retml luminum chmride in which the principle of the invention has been the catalyst- The poly'cycmhexylapplied, but are not to be construed as limiting naphthalenes is highest when a molecular excess the same.

at the cyclohexylating agent is employed. We prefer to employ approximately 2-4 moles of the Example 1 cyclohexylating agent per mole of naphthalene. 1 (1 of a hth e amount of catalyst varies with the particular iifi g fi ggg a i 8 {23: 2: 2 i i m reactants employed and the conditions under Retrol was heated at a temperature of about gfig g g gg ig ggz f g gg 1 :3 a g g gz C. until all of the residual water contained in the Weight of catalyst m; f naphflial a Retrol had been driven 01!. 180.4 grams (2.2

The reaction is conveniently can-[ed out by moles) of cyclohexene was then added, with stirthe f ti i Edi... it? futil fiififiuil lfi ibfiti to a heated mixture 01 nap a cue and e ca alyst, and thereafter continuing the heating and /2 hour after which time the reaction mixture stirring until reaction is complete; 'I'lligoregctior Ives altlloweigl tlodcoolantilfihetcatalysthwasdiilliefieg temperature is usually be ween a ut an rom e q e rs. e was en s e to about 250 0., although somewhat higher temunder vacuum to obtain the following fractions:

Fraction 1 2 a 4 5 Product Unreacted naphtha- Intermediate frac- Mono and di-cye1o- Tri-cyclohoxyl-naphthalenes Higher cyclohexylatcd 5.5 lene. tion. flelzlyl-naphthanaphthalenes.

Appearanee..... Water-whitnllquid C1315 viscous liqvelrgovriggglyiellllzlig Light yellow resin Dark'amber resin. Boiling range... Up to C. at 20 17:32? O. at 20 225312 0. t 26 31:; fiflbalgfilmmtowi" C. Above305 C.at5mm.

I11. l Specific gravity. 1.026 at Ito/130 C so Example 2 330 grams (4.0, moles) of cyclohexene was added gradually with stirring over a period or hour to a heated mixture of 128 grams (1.0 moles) of naphthalene and 3.3 grams 01' anhydrous aluminum chloride. During the addition of cyclohexene the temperature of reaction was maintained at approximately 150-175 C. The reaction mixture was then cooled, and the catalyst was destroyed by acidifying with approximately 200 grams of dilute hydrochloric acid. The acidified mixture was extracted with about 200 grams of toluene and the toluene extract was washed several times with water to remove traces of acid. The toluene was then distilled oil and the residue was lractionally distilled under vacuum as follows:

"m Boiling raugc Yiold Product Grams 233l2 C. at20mm. 35 Unreacted naphthalene and monoand rlicyclohexyl nephalenes.

2 312 C. at Z) mm. to 87 Tri-cyclohexyl-naph- 305 C. at 5 mm. thalenes.

3 305 at 5 mm to 80 Tetra-cyclohexlnaphthalenes. Higher cyclohexylated naphthalenes.

Above 3:50 0. atilinm. 150

Fraction No. 3 was a light yellow brittle resin, having a density oi. approximately 1.016 and a softening point of 95-96 C.

Other modes of applying the principle of our invention may .be employed instead of those explained, change being made as regards the methods herein disclosed or the materials employed, provided the product claimed in any of the following claims be employed.

We therefore particularly point out and distinctly claim as our invention:

A mixture consisting substantially of isomeric tetracyclohexyl-naphthalenes, said mixture being a yellow brittle resin distilling between approximately 305 C. under 5 mm. pressure and apl5 proximately 330 C. under 3 mm. pressure.

FRANK B. SMITH. HAROLD W. MOLL. 

